System and method for portable ultrasonic testing

ABSTRACT

The present disclosure provides a system with an ultrasonic transducer housing assembly that maintains an acoustic coupling path for spherically focused transducers while allowing the placement of the housing at angles relative to a vertical angle. This invention extends the use of spherically focused transducers into portable systems with significantly reduced system and operational costs for non-destructive testing. The transducer housing assembly features a lens housing with an opening that is sealed with a replaceable fluid-tight membrane defining an acoustic window with acoustic properties similar to those of fluid in the housing and therefore at least translucent to the transducer and causing minimal signal loss. The housing contains minimal fluid to be cleaned up in case of improper use or leakage. The transducer housing also includes an optional surface offset and an ability to adjust the focal point of the transducer relative to the component surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to and claims priority from the following US patents and patent applications: this application claims priority from U.S. Provisional Patent Application No. 63/001,608, filed Mar. 30, 2020. Each of the above applications is incorporated herein reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The disclosure relates to the field of ultrasonic non-destructive testing and more specifically to a system and method for ultrasonic non-destructive testing of composite materials that does not require immersion or continuously running water jets.

2. Description of Related Art

Non-destructive Testing (NDT), also known as Non-destructive Evaluation (NDE) or Non-destructive Inspection (NDI), has achieved popularity in testing materials and parts of larger machines as the methods do not generally render the material or part unfit for its intended purpose. Traditional methods of NDT include ultrasonic and thermographic techniques, as well as ones based on the use of eddy currents, radiation (including gamma, X-ray, and microwave), magnetic particles, dye penetrants, and more. NDT has traditionally been used to detect surface flaws of a material, detect delamination of layers of a material, or indicate the presence of other defects within the material.

Prior art patent documents include the following:

U.S. Pat. No. 9,121,817 for Ultrasonic testing device having an adjustable water column by inventors Roach et al., filed Jul. 9, 2012 and issued Sep. 1, 2015, is directed to an ultrasonic testing device having a variable fluid column height is disclosed. An operator is able to adjust the fluid column height in real time during an inspection to to produce optimum ultrasonic focus and separate extraneous, unwanted UT signals from those stemming from the area of interest.

U.S. Pat. No. 10,302,600 for Inspection devices and related systems and methods by inventors Palmer et al., filed Jan. 19, 2016 and issued May 28, 2019, is directed to inspection devices include a nozzle portion having at least one opening and a transducer disposed in a rear chamber of the housing. The housing has at least one fluid channel defined in the housing and extending along at least a portion of the rear chamber. The at least one fluid channel is configured to supply a fluid into a forward chamber of the housing proximate the transducer. Related methods include operating an inspection device.

U.S. Pat. No. 4,215,583 for Apparatus and method for bondtesting by ultrasonic complex impedance plane analysis by inventors Botsco et al., filed Nov. 14, 1978 and issued Aug. 5, 1980, is directed to a non-destructive bond testing apparatus utilizes impedance variation represented by both the phase and amplitude of the signal vector response of a sonic energy generating and receiving probe, which is applied to a laminar, honeycomb or fiber composite structure under test. Typical bonding methods for which this bondtester and method are applicable include adhesive bonding, diffusion bonding, brazing, resistance and impact/friction bonding. A cathode ray tube displays the tip of the vector (as a bright dot) which represents the impedance characteristic affected by the structure under test. A null circuit deletes the response of a non-flawed (or normal) portion of the structure under test so that a flawed (or abnormal) portion of the structure produces an impedance variation from the null point, the variation being represented on a polar coordinate display by the amplitude and angular position of the vector tip, thereby providing diagnostic information regarding the location and type of the bondline condition being detected. Bondline conditions/flaws detectable include, disbonds, adhesive thickness, adhesive porosity, degree of adhesive cure, adhesive (cohesive) strength and forms of in-service adhesive or bondline degradation.

U.S. Pat. No. 4,184,373 for Apparatus for evaluating a bond by inventors Evans et al., filed May 24, 1978 and issued Jan. 22, 1980, is directed to a means and method for evaluating a bond between first and second structures bonded together by an intermediate layer of adhesive. Means are provided for transmitting a pulse of ultrasonic wave energy into the bonded structures whereby a first reflected pulse may be reflected from a first surface of the first structure, a second reflected pulse reflected from the layer of adhesive, and a third pulse possibly reflected from the surface of the second structure adjacent the adhesive layer. Circuit means are provided for sensing the first, second, and third reflected pulses and for providing an indication of the quality of the bond by comparing the amplitudes of the reflected pulses and determining if the ratios lie within predetermined ranges.

U.S. Pat. No. 8,347,723 for Sonic resonator system for testing the adhesive bond strength of composite materials by inventors Questo et al., filed May 21, 2010 and published Jan. 8, 2013, is directed to a sonic resonator system for use in testing the adhesive bond strength of composite materials. Also disclosed herein are a method of calibrating the sonic resonator system to work with a particular composite bond joint, and a method of non-destructive testing the “pass-fail” of the bonded composite bond strength, based on a required bond strength.

US Patent Publication No. 2019/0293610 for Detection of kiss bonds within composite components by inventors Campbell et al., filed Mar. 22, 2019 and issued Sep. 26, 2019, is directed to systems and methods for detecting a kiss bond in a composite component are provided. Using reflected ultrasound data representative of reflected ultrasound energy from the composite component, a first threshold amplitude value between 2% and 5% higher than a predetermined baseline noise amplitude value of expected material noise in the reflected ultrasound energy from the composite component, and a second threshold amplitude value higher than the first threshold amplitude value, one or more occurrences of an amplitude of the reflected ultrasound energy exceeding the threshold amplitude value and less than the second threshold amplitude value are identified. The kiss bond is detected in the composite component based on the identified one or more occurrences of the amplitude of the reflected ultrasound energy.

U.S. Pat. No. 7,574,915 for Simplified impedance plane bondtesting inspection by inventors Kollgaard et al., filed Dec. 28, 2006 and issued Aug. 18, 2009, is directed to an NDI system includes an ultrasonic transducer and an electronic device having an indicator, such as a light source. The electronic device energizes the transducer, receives sinusoidal signals from the transducer, determines impedance-plane coordinates corresponding to quadrature-phase separated components of the sinusoidal signals, and automatically activates the indicator if impedance-plane coordinates exceed a preset threshold. The system may be used in methods of inspecting layered structures such as composite aircraft components and repair patches applied to such structures.

U.S. Pat. No. 8,234,924 for Apparatus and method for damage location and identification in structures by inventors Saxena et al., filed Jul. 16, 2009 and issued Aug 7, 2012, is directed to an apparatus and method for testing composite structures in which ultrasonic waves are used to detect disbonds in the structures are described. The apparatus comprises a flexible structure carrying acousto-optical transducers such as fiber Bragg gratings. During use, the apparatus is mechanically and conformally coupled to the structure under test.

U.S. Pat. No. 7,017,422 for Bond testing system, method, and apparatus by inventors Heyman et al., filed Apr. 2, 2004 and issued Mar. 28, 2006, is directed to a bond strength tester and method for determining certain bond strength parameters of a bonded component, including a phaselocker, a transducer, a loading device that is capable of applying stress-loads to the bond, a controller for controlling the loading device, a data recording device to acquire data, and a computer device to analyze data calculating certain bond strength parameters.

US Patent Publication No. 2014/0216158 for Air coupled ultrasonic contactless method for non-destructive determination of defects in laminated structure by inventors Martin et al., filed Aug. 9, 2012 and published Aug. 7, 2014, is directed to an air coupled ultrasonic contactless method and an installation for non-destructive determination of defects in laminated structures with a width (W) and a multiplicity of n lamellas with intermediate N-1 bonding plants (B), whereas at least one transmitter (T) in a fixed transmitter distance (WTS) radiates ultrasound beams at multiple positions and at least one receiver (R) in a sensor distance (W SR) is receiving re-radiated ultrasound beams at multiple positions relative to the laminated structure (S). The method images the position and geometry of for example lamination defects and allows for inspection of laminated structure (S) of arbitrary height (H) and length (L), and an individual assessment of specific bonding planes (e.g. B1, B2, B3), as well in situations with constrained access to the faces of the sample parallel to the bonding planes.

U.S. Pat. No. 9,360,418 for Nondestructive inspection using hypersound by inventor Georgeson, filed Jul. 17, 2014 and issued Jun. 7, 2016, is directed to a method and apparatus for inspecting an object. The apparatus comprises a wave generator and a detection system. The wave generator is positioned away from an object. The wave generator emits an ultrasonic wave in a direction towards a location on the object such that the ultrasonic wave encounters a portion of the object. The detection system is positioned at a same side of the object as the wave generator. The detection system detects a feature response of a feature within the portion of the object to the ultrasonic wave encountering the portion of the object.

US Patent Publication No. 2020/0230899 for In-situ monitoring of thermoformable composites by inventor Tyson, filed Feb. 1, 2020 and published Jul. 23, 2020, is directed to a method and system for determining the quality and configuration of a structure that is constructed from a thermoformable material, such as a thermoplastic or thermoset material, and in particular thermoplastic composite tapes, where heat is applied to cure the thermoformable material. The quality of the build is monitored during the construction of the structure by determining the differential heat flux in the material as it cools from its elevated temperature. The system and method also may determine the location of defects in a structure being constructed so that remedial measures may be taken or production operations halted to address the defect. A transient thermal effect is applied to the structure being monitored, such as the thermoformable material being applied, which may be implemented from the applied heating of the thermoformable construction application process or additional heating.

U.S. Pat. No. 9,494,562 for Method and apparatus for defect detection in composite structures by inventors Lin et al., filed May 27, 2011 and issued Nov. 15, 2016, is directed to methods and apparatus for non-destructive testing of a composite structure utilizing sonic or ultrasonic waves. In response to a wideband chirp wave sonic excitation signal transmitted from a probe to the composite structure, a probe signal received is correlated with a library of predetermined probe signals and a graphical representation of defects detected is generated. The graphical representation provides detailed information on defect type, defect location and defect shape. Also contemplated is a probe for non-destructive testing of a composite structure comprising three or more transducers wherein each transducer is separately configurable as a transmitter or as a receiver; and a controller coupled to each of transducer for providing signals thereto and receiving signals therefrom, wherein the signals provided thereto include signals for configuring each transducer as either a transmitter or a receiver, and signals for providing an excitation signal from each transducer which is configured as a transmitter.

U.S. Pat. No. 10,444,195 for Detection of near surface inconsistencies in structures by inventor Bingham, filed May 5, 2016 and issued Oct. 15, 2019, is directed to a method of detecting near surface inconsistencies in a structure is presented. A pulsed laser beam is directed towards the structure. Wide-band ultrasonic signals are formed in the structure when radiation of the pulsed laser beam is absorbed by the structure. The wide-band ultrasonic signals are detected to form data. The data is processed to identify a frequency associated with the near surface inconsistency.

US Patent Publication No. 2019/0187107 for Methods for ultrasonic non-destructive testing using analytical reverse time migration by inventors Asadollahi et al., filed December 17, 2018 and published Jun. 20, 2019, is directed to systems and methods for nondestructive testing using ultrasound transducers, such as dry point contact (“DPC”) transducers or other transducers that emit horizontal shear waves, are described. An analytical reverse time migration (“RTM”) technique is implemented to generate images from data acquired using the ultrasound transducers.

US Patent Publication No. 2018/0120268 for Wrinkle Characterization and Performance Prediction for Composite Structures by inventors Georgeson et al., filed Oct. 31, 2016 and published May 3, 2018, is directed to methods that provide wrinkle characterization and performance prediction for wrinkled composite structures using automated structural analysis. In accordance with some embodiments, the method combines the use of B-scan ultrasound data, automated optical measurement of wrinkles and geometry of cross-sections, and finite element analysis of wrinkled composite structure to provide the ability to assess the actual significance of a detected wrinkle relative to the intended performance of the structure. The disclosed method uses an ultrasonic inspection system that has been calibrated by correlating ultrasonic B-scan data acquired from reference standards with measurements of optical cross sections (e.g., micrographs) of those reference standards.

U.S. Pat. No. 10,605,781 for Methods for measuring out-of-plane wrinkles in composite laminates by inventors Grewel et al., filed Mar. 9, 2018 and issued Mar. 31, 2020, is directed to methods for measuring out-of-plane wrinkles in composite laminates are described. An example method includes scanning a first side of a composite laminate with an ultrasonic transducer. The method further includes locating an out-of-plane wrinkle of the composite laminate on a B-scan ultrasound image generated in response to the scanning of the first side of the composite laminate. The method further includes associating a first marker with the B-scan ultrasound image, the first marker determined based on a location of a crest of the out-of-plane wrinkle on the B-scan ultrasound image. The method further includes associating a second marker with the B-scan ultrasound image, the second marker determined based on a location of a trough focal point of the out-of-plane wrinkle on the B-scan ultrasound image. The method further includes determining an amplitude of the out-of-plane wrinkle based on a distance between the first marker and the second marker.

U.S. Pat. No. 10,161,910 for Methods of non-destructive testing and ultrasonic inspection of composite materials by inventors Dehghan-Niri et al., filed Jan. 11, 2016 and issued Dec. 25, 2018, is directed to a method of non-destructive testing includes locating an ultrasonic transducer with respect to a component having a visually-inaccessible structure to collect B-scan data from at least one B-scan of the component and to collect C-scan data from at least one C-scan of the component. The method also includes filtering the B-scan data and the C-scan data to remove random noise and coherent noise based on predetermined geometric information about the visually-inaccessible structure to obtain filtered data. The method further includes performing linear signal processing and nonlinear signal processing to determine a damage index for a plurality of voxels representing the visually-inaccessible structure from the filtered B-scan data and the filtered C-scan data to generate a V-scan image. A method of non-destructive testing of a wind turbine blade and an ultrasound system are also disclosed.

U.S. Pat. No. 7,895,895 for Method and apparatus for quantifying porosity in a component by inventors Kollgaard et al., filed Jul. 23, 2007 and issued Mar. 1, 2011, is directed to a computer implemented method, or hardware filtration apparatus, and computer usable program code for measuring porosity in materials. An ultrasonic signal is emitted from a transmitting transducer in an ultrasonic measurement system into a material. A response signal is received at a receiving transducer in the ultrasonic measurement system from the material. The response signal is filtered to pass only frequencies in the response signal within a selected frequency range to form a filtered response signal. A porosity level of the material is identified using the filtered response signal.

U.S. Pat. No. 8,522,615 for Simplified direct-reading porosity measurement apparatus and method by inventors Brady et al., filed Nov. 30, 2010 and issued Sep. 3, 2013, is directed to an apparatus for measuring porosity of a structure includes an ultrasonic transducer device configured to be pressed against a structure, the ultrasonic transducer device being further configured to emit ultrasonic pulses into the structure and detect echo profiles; and an electronic device including: a manager having an interface gate, a back-surface sensing gate and a back surface analysis gate; a pulse generator interfacing with the manager and the ultrasonic transducer device; a data acquisition device interfacing with the ultrasonic transducer device and the manager; and a display having a porosity indicator interfacing with the manager.

U.S. Pat. No. 7,010,980 for Method of determining the porosity of a workpiece by inventor Meier, filed Jun. 28, 2004 and issued Mar. 14, 2006, is directed to the porosity of a workpiece, in particular a workpiece made of a fiber composite material is determined. An ultrasonic signal is injected into the workpiece and an ultrasonic echo signal is received from the workpiece. The variation of the amplitude of the ultrasonic echo signal with respect to the depth is used as a measure of the porosity of the workpiece material at the respective depth.

U.S. Pat. No. 6,959,602 for Ultrasonic detection of porous medium characteristics by inventors Peterson et al., filed Mar. 12, 2003 and issued Nov. 1, 2005, is directed to plate waves are used to determine the presence of defects within a porous medium, such as a membrane. An acoustic wave can be propagated through a porous medium to create a plate wave within the medium. The plate wave creates fast compression waves and slow compression waves within the medium that relate to the material and structural properties of the medium. The fast compression wave provides information about the total porosity of a medium. While the slow compression wave provides information about the presence of defects in the medium or the types of materials that form the medium.

U.S. Pat. No. 9,297,789 for Differential ultrasonic waveguide cure monitoring probe by inventors Djordjevic et al., filed Sep. 20, 2012 and issued Mar. 29, 2016, is directed to a new methodology, testing system designs and concept to enable in situ real time monitoring of the cure process. Apparatus, system, and method for the non-destructive, in situ monitoring of the time dependent curing of advanced materials using one or more differential ultrasonic waveguide cure monitoring probes. A differential ultrasonic waveguide cure monitoring probe in direct contact with the material to be cured and providing in situ monitoring of the cure process to enable assessment of the degree of cure or cure level in a non-cure related signal variances (e.g., temperature) independent calibrated response manner. A differential ultrasonic waveguide cure monitoring probe including a transducer coupled to a waveguide and incorporating correction and calibration methodology to accurately and reproducibly monitor the cure process and enable assessment of cure level via ultrasonic reflection measurements. The amplitude of the corrected interface response signal reflected from the probe-resin interface indicating changes in the modulus of the material during the cure.

U.S. Pat. No. 6,945,111 for System and method for identifying incompletely cured adhesive by inventor Georgeson, filed Sep. 28, 2004 and issued Sep. 20, 2005, is directed to a system for inspecting adhesive in a composite structure, such as for soft or improperly cured regions, includes a transducer and a processing element. The transducer can transmit a signal, such as an ultrasonic signal, into the adhesive such that at least a portion of the ultrasonic signal can propagate through the adhesive, reflect off of an interface between the adhesive and another material, and propagate back through the adhesive. Upon exiting the adhesive, then, the transducer can receive a reflected portion of the ultrasonic signal. Thereafter, the processing element can identify a defect, such as soft or improperly cured regions, in the adhesive upon a relationship of an amplitude of the reflected portion of the reflected ultrasonic signal to a predefined threshold.

U.S. Pat. No. 10,697,941 for Method and system of non-destructive testing for composites by inventors Jack et al., filed Mar. 20, 2013 and issued Jun. 30, 2020, is directed to method and system are disclosed for characterizing and quantifying composite laminate structures. The method and system take a composite laminate of unknown ply stack composition and sequence and determine various information about the individual plies, such as ply stack, orientation, microstructure, and type. The method and system can distinguish between weave types that may exhibit similar planar stiffness behaviors, but would produce different failure mechanisms. Individual ply information may then be used to derive the laminate bulk properties from externally provided constitutive properties of the fiber and matrix, including extensional stiffness, bending-extension coupling stiffness, bending stiffness, and the like. The laminate bulk properties may then be used to generate a probabilistic failure envelope for the composite laminate. This provides the ability to perform non-destructive QA to ensure that individual lamina layup was accomplished according to specifications, and results may be used to identify a numerous laminate properties beyond purely structural.

U.S. Pat. No. 10,345,272 for Automated calibration of non-destructive testing equipment by inventors Holmes et al., filed Jul. 13, 2015 and issued Jul. 9, 2019, is directed to a method for auto-calibrating a non-destructive testing instrument. In accordance with some embodiments, the method comprises: (a) determining a first set of coordinates in a test object coordinate system of the test object, the first coordinates representing a target position on a surface of the test object; (b) storing a calibration file in a memory of the non-destructive testing instrument, the calibration file containing calibration data which is a function of structural data representing a three-dimensional structure of the test object in an area containing the target position; (c) calibrating the non-destructive testing instrument using the calibration data in the calibration file; and (d) interrogating the target position using the calibrated non-destructive testing instrument.

U.S. Pat. No. 5,408,882 for Ultrasonic device and method for non-destructive evaluation of polymer composites by inventors McKinley et al., filed Jul. 21, 1993 and issued Apr. 25, 1995, is directed to an ultrasonic measurement device and a method for a non-destructive evaluation of polymer composites having discontinuous fibers distributed therein. The device has one or a plurality of substantially matched pairs of transducers disposed on wedge shaped focuser and a relay, the focuser and relay each have their impedances substantially matched to that of the polymer composite being analyzed. The device is placed on a surface of the composite with the apexes of the focuser and relay in close contact with the surface. A velocity of a substantially longitudinal ultrasonic wave generated by the first transducer and received by the second transducer after its passage through the composite is determined at several angles of orientations about a center point, and the measured velocities of the ultrasonic wave are processed through a computer having software to determine the physical attributes of the composite, such as weight percentage of fibers present in the composite, Young's modulus, shear modulus and Poisson's ratio of the composite.

U.S. Pat. No. 10,761,067 for Method and system for non-destructive testing of curved composites by inventors Jack et al., filed Sep. 8, 2015 and issued Sep. 1, 2020, is directed to characterizing and quantifying composite laminate structures, including structures with surfaces that are curved in two and three dimensions. The embodiments take a composite laminate of unknown ply stack composition and sequence and determine various information about the individual plies, such as ply stack, orientation, microstructure, and type. The embodiments can distinguish between weave types that may exhibit similar planar stiffness behaviors, but would produce different failure mechanisms. Individual ply information may then be used to derive the laminate bulk properties from externally provided constitutive properties of the fiber and matrix, including extensional stiffness, bending-extension coupling stiffness, bending stiffness, and the like. The laminate bulk properties may then be used to generate a probabilistic failure envelope for the composite laminate. In some embodiments, ply stack type and sequence may also be determined for a curved carbon fiber composite using the disclosed embodiments by adding a rotational stage.

US Patent Publication No. 2020/0047425 for Structural Health Monitoring of Curved Composite Structures Using Ultrasonic Guided Waves by inventors Jahanbin et al., filed Aug. 9, 2018 and published Feb. 13, 2020, is directed to systems and methods for non-destructive inspection of curved composite laminate structures using interface guided waves. In particular, if the curved composite laminate structure has a noodle, then the noodle area may be inspected using interface guided waves. The systems and methods provide a repeatable and reliable nondestructive technique for monitoring the structural health of the noodle area of an adhesively bonded curved composite laminate structure by comparing detection data acquired from an inspected curved composite laminate structure with prediction data derived using a simulated curved composite laminate structure.

U.S. Pat. No. 7,975,549 for Method, apparatus and system for inspecting a workpiece having a curved surface by inventors Fetzer et al., filed Jun. 19, 2007 and issued Jul. 12, 2011, is directed to a non-destructive inspection method, apparatus and system are provided for inspecting a workpiece having a curved surface with at least one predefined radius of curvature. The apparatus, such as an inspection probe, includes a plurality of transducer elements positioned in an arcuate configuration having a predefined radius of curvature and a curved delay line. The curved delay line has an outer arcuate surface having a predefined radius of curvature that matches the predefined radius of curvature of the transducer elements. The curved delay line also has an inner arcuate surface that has at least one predefined radius of curvature that matches the at least one predefined radius of curvature of the curved surface of the workpiece. In addition to the inspection probe, the system includes an excitative source for triggering the transducer elements to emit signals into the workpiece and a computing device to receive the return signals.

SUMMARY OF THE INVENTION

The present invention relates to systems and methods of non-destructive testing using ultrasonic transducers.

It is an object of this invention to provide a system for ultrasonic non-destructive testing wherein the transducer does not contact a test material, without the use of an immersion tank or water jets.

In one embodiment, the present invention is directed to a system for ultrasonic testing of composite materials, including a central housing, having a front end and a back end, defining an interior sealed chamber, a transducer, wherein the transducer is located within the interior sealed chamber of the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid, and wherein the transducer is operable to emit and receive ultrasonic waves.

In another embodiment, the present invention is directed to a method for ultrasonic testing of composite materials, including providing a transducer housing assembly including a central housing, having a front end and a back end, defining an interior sealed chamber, a transducer, wherein the transducer is located within the interior sealed chamber of the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid; and the transducer emitting ultrasonic waves into a test material; and the transducer housing assembly receiving ultrasonic waves reflected from the test material.

In yet another embodiment, the present invention is directed to a system for ultrasonic testing of composite materials, including a central housing, having a front end and a back end, defining an interior sealed chamber, a coupling element sealingly engaged with the back end of the central housing and coupled with a transducer, wherein adjustment of the coupling element moves the transducer relative to the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid; and wherein the transducer is operable to emit and receive ultrasonic waves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an orthogonal side view of a transducer housing assembly according to one embodiment of the present invention.

FIG. 2 illustrates an orthogonal side view of a transducer housing assembly according to one embodiment of the present invention.

FIG. 3 illustrates an isometric view of the transducer housing assembly shown in FIG. 1.

FIG. 4 illustrates a top view of the transducer housing assembly shown in FIG. 1.

FIG. 5 illustrates an isometric exploded view of a transducer housing assembly according to another embodiment of the present invention.

FIG. 6 illustrates an orthogonal exploded view of components of the transducer housing assembly shown in FIG. 5.

FIG. 7 illustrates an isometric view of a lens housing according to one embodiment of the present invention.

FIG. 8 illustrates an orthogonal front view of a central housing according to one embodiment of the present invention.

FIG. 9 illustrates an orthogonal front view of a lens housing according to one embodiment of the present invention.

FIG. 10 illustrates an orthogonal front view of a transducer housing assembly, including the housing shown in FIG. 8 paired with the lens housing shown in FIG. 9.

FIG. 11 illustrates an orthogonal front view of the transducer housing assembly shown in FIG. 10, with the lens housing secured in the housing.

FIG. 12 illustrates an orthogonal view of a lens housing according to one embodiment of the present invention.

FIG. 13 illustrates an orthogonal side view of a surface offset element according to one embodiment of the present invention.

FIG. 14 illustrates an orthogonal side view of a transducer housing assembly mounted on a robotic arm.

FIG. 15 is a schematic diagram of a system of the present invention.

DETAILED DESCRIPTION

The present invention is generally directed to systems and methods of non-destructive testing using ultrasonic transducers.

In one embodiment, the present invention is directed to a system for ultrasonic testing of composite materials, including a central housing, having a front end and a back end, defining an interior sealed chamber, a transducer, wherein the transducer is located within the interior sealed chamber of the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid, and wherein the transducer is operable to emit and receive ultrasonic waves.

In another embodiment, the present invention is directed to a method for ultrasonic testing of composite materials, including providing a transducer housing assembly including a central housing, having a front end and a back end, defining an interior sealed chamber, a transducer, wherein the transducer is located within the interior sealed chamber of the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid; and the transducer emitting ultrasonic waves into a test material, and the transducer housing assembly receiving ultrasonic waves reflected from the test material.

In yet another embodiment, the present invention is directed to a system for ultrasonic testing of composite materials, including a central housing, having a front end and a back end, defining an interior sealed chamber, a coupling element sealingly engaged with the back end of the central housing and coupled with a transducer, wherein adjustment of the coupling element moves the transducer relative to the central housing, a fluid connector attached to the central housing, wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the sealed chamber, wherein the front end of the central housing is sealed by a membrane, wherein the membrane is acoustically translucent to the coupling fluid, and wherein the transducer is operable to emit and receive ultrasonic waves.

Due to their high strength-to-weight ratios, composites are becoming increasingly common, particularly for structural applications in the aerospace, automotive, sporting goods, rail, petrochemical, defense and other industries. Manufacturing defects as well as damage caused during use of the composite can have a significant impact on the laminate's structural performance and sometimes lead to structural failure. Damage to a composite can frequently occur as a result of, for example, hail strikes, lightning, bird collisions, mishandling of the part, or general fatigue. Examples of defects that can lead to the failure of a composite material during use include foreign objects within the material, insufficient bonding between the layers of the composite, wrinkling of the layers of the composite, delamination within at least one layer of the composite, incomplete curing of the composite, improper conformance to manufacturing specifications, and excessively large pores within the composite. Therefore, properties such as the bond line thickness, porosity, ply type, delaminations, local failure points, and weave type of the composite can have significant effects on the overall material properties and performance of a composite structure, and they may even serve as crack initiation points.

Ultrasonic inspection is one of the primary NDT techniques currently used in industry to evaluate composite performance and conformity with industry standards. Ultrasonic NDT techniques rely on the propagation and measurement of high-frequency sound waves through the thickness of a structure in order to detect the physical or material properties of the structure. Traditionally, ultrasonic methods have been divided between contact methods and immersion-based methods. In contact methods, transducers are directly applied to the test material to be tested, with a thin film of coupling fluid (e.g. water, gel, grease, oil, etc.) disposed in between the transducer and the test material. Immersion methods do not involve contact between the transducer and the test material, but instead utilize a large tank of coupling fluid, typically water, in which both the material and transducer are placed. The coupling fluid allows the waves produced by the transducer to easily travel to the test material and data can be recorded from the resulting reflections and refractions of the wave. Alternatives to the immersion method include running a continuous jet of coupling fluid over the test material for the duration of the test in order to allow the transducer to be coupled to the material without a large and often expensive tank. Transducers used during immersion type testing are often spherically focused, which allows the transducers to achieve improved resolution and sensitivity relative to contact transducers.

Both contact transducers and immersion type transducers traditionally include one of two different configurations for operation. In pulse-echo, or reflection, ultrasonic configurations, a transducer generates high-frequency ultrasonic energy, which is introduced to and transmitted through the surface of the test material in waves. The use of such systems typically requires an acoustic medium (e.g., water, gel) to bridge the gap between the transducer and the test material. As the waves propagate through the thickness of the test material, discontinuities within the test material (due to material changes, cracks, delaminations, foreign objects, etc.) cause a reflection of the wave, which can then be detected by the transducer and displayed or characterized. In contrast, in through transmission, or attenuation, ultrasonic configurations, a transducer generates high frequency ultrasonic energy, which is transmitted through one side of a test material and then received by a corresponding receiver on the opposite side of the test material. As the waves propagate through the thickness of the test material, discontinuities within the test material may cause waves in some areas to be slowed or fully attenuated before they reach the receiver. The receiver can then characterize the test material by measuring the degree of attenuation of the ultrasonic wave.

In selecting ultrasonic inspection systems, the constraints of portability and robustness are often inversely proportional to high resolution and fidelity. When attempting to optimize both portability and robustness, most inspectors currently select a contact transducer. Contact transducers allow an inspector to quickly place a thin gel on a part to be inspected and place the transducer in intimate contact with the part. Data can be quickly gathered and at the same time, the system can operate on a variety of surfaces and environmental conditions. The primary downside of this approach is the resolution of the acquired data. The planar resolution of the transducer is dictated by the physical footprint of the transducer. This footprint can be mitigated by fabricating smaller and smaller transducers. The through-thickness resolution of the transducer, however, is determined by the frequency of the transducer and the power with which it can be fired. As a transducer's planar dimension is reduced, both the power that can be sent to fire the transducer and the frequency is simultaneously reduced. Thus, improvements to planar resolution are in direct conflict with improvements in through thickness resolution.

An alternative to the contact transducer is a spherically focused transducer. These transducers are capable of operating at high frequencies (25-50 MHz) and have a planar resolution as fine as can be machined into the transducer housing lens, which may be less than 1/10th of a millimeter. However, spherically focused transducers can only operate when the transducer is acoustically coupled to the surface of a component being inspected. Acoustically coupling the transducer to the test material requires immersing the transducer in an acoustic medium while ensuring the transducer has a viable acoustic path between it and the surface to be tested. Water is the most widely used acoustic medium for immersion transducers, as the difference in acoustic impedance between the water and transducer lens is minimal.

Currently, there are two main techniques to achieve a viable acoustic coupling water path: full immersion tank testing or water jets. The full immersion tank requires the part to be submerged in water, thus preventing many larger components, such as aircraft wings and fuselages, from being tested without a substantial (and often impractical) infrastructure investment. Water jets, on the other hand, require water to be spraying in all directions, which causes water to pool under the component being scanned. Water jets therefore also require infrastructure investments, often in the form of grates to collect the sprayed water, pumps to circulate the water, and framing to protect equipment in the area that can be damaged by water.

One alternative to the use of traditional water jets is a “bubbler”. To use a bubbler, a temporary watertight box is built around a region of a component to be scanned for inspection. Water is then poured into a column that houses the transducer and is allowed to slowly leak out from a base of the box. This approach requires a new box to be installed at every new location for the scan. In order for a bubbler to work, the membrane must be pressed tightly against the object to be tested, as water leaks out slowly enough from the bubbler that it cannot maintain the blast pressure necessary to allow the device to be placed at an offset from the test material. Not only does this create the risk of impact between the bubbler and the test material, which may cause damage, but it also greatly reduces the resolution of the device. Bubblers rely on permeable membranes that slowly allow the water to leak out, but when the bubbler is operating and the membrane is pressed firmly against the test surface, the systems cannot effectively distinguish between waves in the membrane and in the test material, rendering the devices less effective if not entirely inoperable. Furthermore, bubblers suffer from similar drawbacks as traditional water jets, in that they require water to be pumped in constantly and require a means to catch leaking water. Additionally, full immersion, traditional water jets, and the bubbler all require the test material to be exposed to water, which is undesirable in some situations.

Traditional water jets and bubblers also suffer similar problems of being unable to scan hard to reach areas of a device. Hard to reach areas are often semi-contained within a device or component to be tested and therefore, the use of traditional water jets is highly likely to cause water to pool within the device, which may cause damage or be difficult to pump out. Furthermore, both traditional water jet systems and bubblers require the continuous pumping in of water via a water column. However, the need for this water column eliminates the ability of those devices to effectively navigate to hard-to-reach areas of a device or component to be tested.

As of yet, no other efforts to produce a robust functional ultrasonic scanner utilizing water-filled chambers have been successful. Some existing systems require the chamber to leak around a rolling ball, through a permeable membrane, or otherwise, to span the gap between the chamber and the surface to be measured. Such systems still require a flow of water into the chamber to replenish the water loss to maintain the acoustic coupling and require contact between the water and the test material. Other systems sacrifice the use of a spherically focused transducer and therefore have decreased resolution. Still other systems have fixed focal lengths, and other systems have fixed lengths of lens housing and lens that preclude reaching portions of surfaces for scanning.

Therefore, there remains a need to provide a more simplified and versatile system, including a housing for an ultrasonic spherically focused transducer that can be operated independently of a full immersion tank and yet be used to scan omnidirectionally from a sealed fluid-tight housing for acoustic coupling with a component surface.

Additionally, traditional ultrasonic testing devices utilize calibration blocks. Before testing, the testing device is used on one or more calibration blocks, which typically are either an exemplary form of the material to be tested or a material with known defects. Traditional ultrasonic inspection systems use this calibration method as a means of comparison in determining whether the signals reflected from the test material match or differ from those of the calibration block. However, reliance on calibration blocks weakens the ability to specifically indicate important properties of a test material. For example, during porosity testing, traditional systems may recognize calibration blocks with porosities of 0.2, 0.4 and 0.6, but a test material which most closely aligns with the 0.4 porosity calibration block may still have a porosity of anywhere between 0.3 and 0.5, with further specificity being limited. Furthermore, testing using calibration blocks may be hindered by unknown flaws in the calibration blocks or unconsidered confounding variables that differ between the calibration blocks and the actual test material. Therefore, a system is needed that is capable of directly determining qualities of a material, such as ply orientation, porosity, bond line thickness, the presence of wrinkles, unevenness in the bond line, or other important physical properties of a composite material without reference to a calibration block.

The present disclosure provides a system with a transducer housing assembly that maintains an acoustic coupling path needed for the spherically focused transducers while allowing placement of the housing at any angle relative to a vertical plane. The system enables the use of higher-resolution immersion-type ultrasonic transducers without the complete water immersion or water jets typically required for both the transducer and the component to be scanned with the transducer. This invention extends the use of the spherically focused transducers into portable systems and can significantly reduce operational costs and complexity.

The system with the transducer housing assembly features a lens housing with an opening sealed by a replaceable fluid-tight membrane. The membrane forms an acoustic window with acoustic properties similar to those of the fluid in the housing and therefore acoustically transparent or at least acoustically translucent to the transducer and causing minimal signal loss. The transducer housing also includes the ability to coarsely and finely adjust the focal point of the transducer relative to the component surface. This feature allows adjustments for individual transducers having different focal points relative to the transducer housing, and allows an operator to focus at different depths within the part. Another feature is the ability to quickly replace the fluid-tight membrane coupled to the lens housing, if the film becomes damaged during use. The transducer housing assembly in operation contains a small volume of fluid, so that even if the film becomes damaged, the spilled fluid can simply be cleaned up with a small typical shop rag, without requiring inconvenient or expensive set ups to catch leaked fluid.

In at least one embodiment, the transducer housing assembly, with the transducer, can fit within a 5 cm×5 cm×15 cm volume. The transducer housing assembly with the acoustic transducer can be connected to a variety of translation devices, including robotic arms. The system allows for non-destructive scanning in a pulse echo configuration using immersion-type ultrasonic transducers without requiring typical full immersion tank testing or water jets. By implementing high-resolution immersion transducers, the technology overcomes the resolution limitations of current portable scanners that conventionally have relied on contact transducers.

The transducer housing assembly is capable of operating on a variety of composite materials, especially those commonly used in automotive and aerospace applications, including carbon fiber, fiberglass, concrete, and other composite materials. In one embodiment, the transducer housing assembly is used to test materials with a thickness between 1/16 of an inch and ½ of an inch. In another embodiment, the transducer housing assembly is used to test materials with a thickness greater than ½ of an inch, including laminates with a thickness of greater than 2 inches.

The present invention utilizes the transducer housing assembly is used to determine qualities of a material, including the porosity of the material, the ply orientation of the material, whether material layers are a weave or unidirectional, the presence of wrinkles in the layers of the material, bond line thickness, inconsistencies in the bond line, the presence of foreign objects in the material, and the presence of internal defects within the material without use of a calibration block. Therefore, the transducer housing assembly is able to directly measure these quantities and provide a quantifiable output via a display means, instead of merely determining whether the sample matches some previously scanned control material.

The transducer housing assembly is able to used in conjunction with other testing devices for testing of larger structures. In one embodiment, a separate phase array scanner is used to scan over a large area of a test material and identify potential problem areas in the material. Subsequently, the transducer housing assembly is used to more precisely scan the identified potential problem areas. In another embodiment, a thermographic scan of a material is first performed before the transducer housing assembly is used to more precisely scan areas identified by the thermographic scan. In yet another embodiment, a thermographic scan is performed first on a component, followed by a phase array scan of a subarea of the component, and finally the transducer housing assembly is used to scan individual parts of the subarea of the component.

FIG. 1 illustrates an orthogonal side view of a transducer housing assembly 4 according to one embodiment of the present invention. The transducer housing assembly 4 includes a central housing 6 with a front portion 10 and a back portion 8. In one embodiment, the front portion 10 and back portion 8 are hollow cylindrical pieces and are integrally formed with each other. Alternatively, the front portion 10 and back portion 8 are not integrally formed but are separately formed and are joined together via any chemical and/or mechanical means known in the art. In another embodiment, the front portion 10 and back portion 8 are another shape, such as rectangular prisms. In one embodiment, the diameter of the front portion 10 is greater than that of the back portion 8, with the diameter of the central housing 6 tapering down between the front portion 10 and back portion 8 at a midsection 9. The central housing 6 is attached to a fluid connector 24. In one embodiment, the fluid connector 24 is attached to the front portion 10 of the central housing 6, while in another embodiment, the fluid connector 24 is attached to the midsection 9 or back portion 8 of the central housing 6. In one embodiment, a mounting bracket 26 extends from the front portion 10 of the central housing 6. In another embodiment, the mounting bracket 26 extends from the midsection 9 or back portion 8 of the central housing 6.

The front portion 10 of the central housing 6 is connected to a lens housing 20, which extends outwardly from the front end of the central housing 6. The front end of the lens housing 20 includes an opening 22. In one embodiment, at least one surface offset element 28 extends from the front end of the central housing 6. In another embodiment, the surface offset elements 28 extend outwardly directly from the lens housing 20. Transducer is disposed within the central housing 6. In some embodiments, the transducer is directly attached to an elongate member 52. The elongate member 52 is attached to the central housing 6 by means of a coupling element 16. In one embodiment, the position of the elongate member 52, and therefore the transducer, can be adjusted relative to the central housing 6 by rotating or otherwise adjusting the coupling element 16.

In one embodiment, the elongate member 52 and coupling element 16 include a metal material, such as, but not limited to, steel or aluminum. In another embodiment, the elongate member 52 and coupling element 16 are formed of the same metal material. Forming both the elongate member 52 and coupling element 16 from the same metal material is advantageous, as it prevents one of the elements acting as a cathode or an anode, which would allow for galvanic cell activity in the transducer housing assembly 4, shortening the useful life of the device. In one embodiment, the central housing 6 is formed from a plastic, such as polycarbonate or polyethylene. In another embodiment, the central housing 6 is formed via 3D printing of the device using an ultraviolet (UV) curable polymer, which is then cured after formation.

In one embodiment, as shown in FIG. 1, the mounting bracket 26 includes a first plane 262 extending away from the central housing 6 at an angle and a second plane 263 extending from the end of the first plane 262 in a direction substantially parallel to a central axis of the transducer housing assembly 4. In another embodiment, as shown in FIG. 5, the mounting bracket 26 is a substantially rectangular piece disposed between and orthogonal to the front portion 10 and back portion 8 of the central housing 6. As can be seen in FIG. 2, in other embodiments, the mounting bracket 26 takes different shapes, depending on the device to which it is to be attached.

FIG. 3 illustrates an isometric view of the transducer housing assembly 4 shown in FIG. 1. FIG. 4 illustrates a top view of the transducer housing assembly shown in FIG. 1. As can be seen in FIGS. 3 and 4, in one embodiment, the transducer housing assembly 4 includes three surface offset elements 28. In one embodiment, the mounting bracket 26 includes at least one attachment bore 261

FIG. 5 illustrates an isometric exploded view of a transducer housing assembly 4 according to another embodiment of the present invention. In one embodiment, the fluid connector 24 is attached to the central housing 6 of the transducer housing assembly 4 by connecting to a connection port 34. In one embodiment, the fluid connector 24 connects to the connection port 34 by means of threading located on the outside surface of the fluid connector 24 and the interior surface of the connector port 34.

In one embodiment, the coupling element 16 is a hollow cylinder and the elongate member 52 extends through the coupling element 16. The elongate member 52 and the coupling element 16 are held together by frictional contact between the outside surface of the search tube 52 and the interior surface of the coupling element. As shown in FIG. 6, in another embodiment, the elongate member 52 is secured to the coupling element 16 by a securing element 54. In one embodiment, the securing element 54 is a screw, bolt, or compressible pin. In one embodiment, the elongate member 52 is a hollow cylinder with the transducer 50 being frictionally engaged within a front end of the elongate member 52.

In one embodiment, the coupling element 16 connects to the central housing 6 by means of threading on part of the surface of the coupling element 16 and on the inner surface of a first opening 12 in the back portion 8 of the central housing 6. In another embodiment, when the coupling element 16 is engaged with the central housing 6, the coupling element 16 can be rotated so as move the coupling element 16 and the elongate member 52 longitudinally relative to the central housing 6. In yet another embodiment, the securing element 54 can be removed, compressed or otherwise altered, which allows the coupling element 16 and the elongate member 52 to move longitudinally relative to the central housing 6. By moving the elongate member 52 longitudinally relative to the central housing 6, the position of the transducer 50 is able to be changed, which allows for accommodation of a range of sizes for transducers 50, as well as greater precision in the focusing on the transducer.

In one embodiment, the first opening 12 includes sealing elements, which prevent fluid leakage through the first opening 12. In one embodiment, the sealing elements include O-rings lining the inner surface of the first opening 12. In another embodiment, the chamber within the central housing 6 is not fully sealed during operation, with either the back end of the central housing 6 or the interface with the fluid connector 24 being left unsealed. The option to use the transducer housing assembly 4 without sealing the chamber of the central housing provides flexibility in the parts used to construct the device, including allowing for the reduction of manufacturing cost. However, for use of the transducer housing assembly 4 that involves putting the transducer housing assembly 4 at an angle, it is advisable to sealed the interior chamber to prevent fluid leakage, which could cause decoupling of the transducer to the test material.

The front portion 10 of the central housing 6 further includes a second opening 18. The lens housing 20 is inserted into the second opening 18 in order to engage the lens housing 20 with the central housing 6. In one embodiment, the lens housing 20 and central housing 6 are engaged by means of threading on the exterior surface of the lens housing 20 and on the interior surface of the second opening 18. In another embodiment, the lens opening 20 includes annular or helical grooves 58, within which sealing elements are attached. When the lens opening 20 placed into the second opening 18, the sealing elements engage with the interior surface of the second opening 18 and form a fluid-tight seal. In one embodiment, the sealing elements are O-rings. In yet another embodiment, the second opening 18 includes at least one engagement notch 32 and the lens housing 20 includes at least one engagement protrusion 30, as shown in FIG. 7. As shown in FIGS. 8-11, in order for the lens housing 20 to be placed within the second opening 18, the at least one engagement protrusion 30 of the lens housing 20 must align with the at least one engagement notch 32 of the second opening 18. After the lens housing 20 is placed within the second opening 18, the lens housing 20 is turned such that the at least one engagement protrusion 30 no longer aligns with the at least one engagement notch 32. In one embodiment, the lens housing 20 is easily separated from the central housing 6 by twisting the lens housing 20 and pulling it out. This is advantageous in the event that the lens housing 20 becomes damaged and needs to be replaced, or where lens housings 20 of different sizes are needed in order examine different parts of a component.

FIG. 6 illustrates an orthogonal exploded view of components of the transducer housing assembly shown in FIG. 5. The fluid connector 24 is able to be connected to one end of a conduit 36, such as a hose or a pipe. In on embodiment, the other end of the conduit 36 is connected to a fluid pump or fluid reservoir, from which fluid is able to be introduced through the conduit 36 and the fluid connector 24 into the sealed chamber. In another embodiment, the transducer housing assembly 4 is not connected to a fluid pump and fluid is added to the central housing 6 by other means, such as manual pouring.

In one embodiment, the fluid connector 24 includes a pressure relief valve, which allows fluid to escape when the volume of fluid exceeds the volume of the sealed chamber. The pressure relief valve therefore advantageously provides an adjustable volume of fluid into the sealed chamber, depending on the distance between the transducer 50 and the front end of the central housing 6. In one embodiment, the fluid connector 24 is able to be connected to a pump and air is pumped out of the sealed chamber before or while filling the chamber with a coupling fluid. Pumping out air helps to assure a lack of bubbles in the fluid, which improves the acoustic coupling path between the transducer 50 and a component to be tested. Furthermore, after testing has completed, the air pump is able to be used to pump air into sealed chamber, which assists in removing remaining fluid, reducing prolonged exposure to the coupling fluid, which could cause damage to the transducer housing assembly, such as corrosion.

FIG. 12 illustrates an orthogonal view of a lens housing 20 according to one embodiment of the present invention. A membrane 38 is placed over the front end of the lens housing 20. The membrane 38 creates a fluid-tight seal on the front end of the lens-housing 20. When the lens housing 20 with the membrane 38 is placed into the central housing 6, a sealed chamber is formed within the central housing 6. The sealed chamber is a fluid-tight chamber, which is sealed by a combination of the interface between the coupling element 16 and first opening 12 of the back portion 8 of the central housing 6, the interface between the lens housing 20 and the second opening 18 of the front portion 10 of the central housing 6, the membrane 38, and the fluid connector 24. In one embodiment, the membrane 38 is secured to the lens housing 20 by at least one retainer 40. In one embodiment, the at least one retainer 40 includes at least one O-ring surrounding a portion of the lens housing 20 and pressing the membrane 38 tightly against the lens housing 20. Advantageously, in the event that membrane 38 is punctured or otherwise is unable to effectively seal the sealed chamber, it may easily be replaced by removing the retainer 40, refitting a new membrane, and then reapplying the retainer 40.

The membrane 38 is acoustically transparent or translucent with respect to fluid in the sealed chamber. The material used for the membrane 38 is selected to have a similar acoustic impedance, and therefore similar stiffness and density, as the fluid in the sealed chamber. In one embodiment, the fluid is water or another fluid with an index of refraction approximately equal to 1. In another embodiment, the index of refraction of the membrane 38 is between 0.9 and 1.2. In yet another embodiment, the membrane is made from AQUALENE.

As the frequency of the transducer 50 increases, the temporal resolution quality of the transducer increases. However, as the frequency of the transducer 50 increases, the depth of a material visible to the system decreases due to high frequency attenuation. In one embodiment, the transducer 50 is able to operate at frequencies between 1 and 50 MHz. In a preferred embodiment, the transducer 50 operates between 5 and 15 MHz.

An external couplant can be used to fill the gap between the transducer housing assembly 4 and the test material. In one embodiment, the external couplant is an acoustic gel, such as glycerin, couplant D12, couplant H, a shear wave couplant, or another suitable acoustic gel.

FIG. 13 illustrates an orthogonal side view of a surface offset element according to one embodiment of the present invention. In one embodiment, the surface offset elements 28 include pins 281 attached to a biasing member 282. The biasing member 282 allows the surface offset elements 28 to retract when pressed against the surface of a test material. Furthermore, when the pin 281 is pressed against a test material, the biasing member 282 is able to absorb some of the displacement that would otherwise be imparted to the test material through a force or the transducer housing assembly 4, preventing potential damage to both the transducer housing assembly 4 and the test material. In one embodiment, the degree to which the surface offset elements 28 are able to retract is limited by a stop. When the front of the transducer housing assembly 4 is pressed against a component to be tested, the surface offset elements 28 contact the component first, which prevents damage to the component or to the transducer housing assembly 4 that can be caused by quick and direct contact between the lens housing 20 and the component. Furthermore, by providing a stop to limit the retraction of the surface offset elements 28, the lens housing 20 is able to stay at a fixed and known distance from the component, which allows for improved accuracy during the testing process. In another embodiment, the surface offset elements 28 are threadably connected to the front portion 10 of the central housing 6 and can be manually adjusted before use with different test materials. In one embodiment, the transducer housing assembly 4 operates at an offset distance from the test material approximately equal to one half the thickness of the test material.

In one embodiment, the distance that the transducer housing assembly 4 is offset from the test material is determined using a calibration wave. An initial wave is transmitted via the transducer into the test material. Time of flight data is gathered regarding ultrasonic waves reflecting off of a membrane covering the opening 22 of the lens housing 20, waves reflecting off the front surface of the test material, and waves reflecting off the back surface of the test material. Without the need to input material properties or dimensions of the test material, the transducer housing assembly 4 is able to automatically offset by a fixed distance from the test material based on the results of the time of flight data. In another embodiment, the material properties of the test material, such as the speed of sound, and dimensional data of the test material, such as the thickness, is manually entered, allowing the transducer housing assembly 4 to automatically offset by a fixed distance from the test material without the need for a calibration wave.

FIG. 14 illustrates an orthogonal side view of a transducer housing assembly mounted on a robotic arm. The attachment bore 261 is able to receive a screw, bolt, pin, or other affixing means attached to a robotic arm 48. The robotic arm 48 both allows the transducer housing assembly 4 to reach tighter spaces and allows the device to be held steadily for the duration of the testing, increasing the accuracy of the test. In another embodiment, the mounting bracket 26 is attached to a translation stage. The translation stage operates to move the transducer housing assembly 4 to different positions along an X-Y plane. This is especially advantageous in situations wherein the operator desires to scan large sections of a relatively flat test material.

In one embodiment, the transducer housing assembly 4 is attached to an array element. In another embodiment, the array element includes attachment points for more than one transducer housing assembly 4, allowing multiple transducer housing assemblies 4 to be attached to a single array element, which acts as an array of transducers. The array of transducers is therefore able to scan multiple points of a test material simultaneously, with each individual transducer housing assembly 4 being adjustable, so as to allow the array of transducers to scan components with uneven surfaces or scan components having multiple different material types.

In another embodiment, the transducer housing assembly 4 is manually operated. By way of example, the transducer housing assembly 4 may be placed into an assembly attached to the test material. An operator is then able to manually slide the transducer housing assembly 4 within the assembly while the assembly ensures that the transducer housing assembly 4 remains at a substantially fixed distance from the test material. In still another embodiment, the transducer housing assembly 4 is able to automatically move to a plurality of different points on the test object based on preset position data entered into a computer or attached display.

In one embodiment, the elongate member 52 is attached to a connection receiving end. In another embodiment, the connection receiving end attached to the elongate member 52 is connected to a first end of a cable. The second end of the cable is connected to an output display device. Examples of an output display device include a pulser receiver. In one embodiment, the pulser receiver is able to connect to a multiple transducer housing assemblies simultaneously. In one embodiment, the connection receiving end is a UHF connector, a Bayonet Neill-Concelman (BNC) connector, or a Universal Serial Bus (USB) connector. In another embodiment, the connection receiving end is a wireless adapter, allowing the transducer housing assembly 4 to wireless connect with the pulser receiver. The pulser receiver is connected to a computer, having a processor and memory. Furthermore, the computer includes display means for outputting graphical results of ultrasonic testing performed using the transducer housing assembly 4. In yet another embodiment, the computer is also connected with the robotic arm, translation stage, or array element to which the transducer housing assembly 4 is attached and is operable to issue control instructions to the robotic arm, translation stage, or array element.

The computer is connected to a display means able to display a graphical user interface (GUI), which is able to display the results of the testing after processing by the pulser receiver. In another embodiment, a display is directly mounted to the transducer housing assembly 4, which allows results to be displayed to the user of the transducer housing assembly 4 without the operator needing to step away to check the computer. The GUI is able to accept a variety of input factors before each test, including the operator's name, the time, and material properties including the speed of sound of the material to be tested, the thickness of the material to be tested, the stiffness of the material to be tested, or the type of material to be tested. In one embodiment, the GUI is also able to accept a range of locations and a run time, indicating where the robotic arm, the array element, or the translation stage should position itself for testing.

The GUI is capable of displaying information regarding a variety of factors of a laminate, including the location and depth of foreign objects within the laminate, the ply orientation of the laminate, the location of wrinkles within the laminate, the thickness of the bond line of the laminate, areas of incomplete bonding along the bond line of the laminate, the porosity of the laminate, and the location, depth, and size of internal defects and areas of delamination within the laminate.

FIG. 15 is a schematic diagram of an embodiment of the invention illustrating a computer system, generally described as 800, having a network 810, a plurality of computing devices 820, 830, 840, a server 850, and a database 870.

The server 850 is constructed, configured, and coupled to enable communication over a network 810 with a plurality of computing devices 820, 830, 840. The server 850 includes a processing unit 851 with an operating system 852. The operating system 852 enables the server 850 to communicate through network 810 with the remote, distributed user devices. Database 870 is operable to house an operating system 872, memory 874, and programs 876.

In one embodiment of the invention, the system 800 includes a network 810 for distributed communication via a wireless communication antenna 812 and processing by at least one mobile communication computing device 830. Alternatively, wireless and wired communication and connectivity between devices and components described herein include wireless network communication such as WI-FI, WORLDWIDE INTEROPERABILITY FOR MICROWAVE ACCESS (WIMAX), Radio Frequency (RF) communication including RF identification (RFID), NEAR FIELD COMMUNICATION (NFC), BLUETOOTH including BLUETOOTH LOW ENERGY (BLE), ZIGBEE, Infrared (IR) communication, cellular communication, satellite communication, Universal Serial Bus (USB), Ethernet communications, communication via fiber-optic cables, coaxial cables, twisted pair cables, and/or any other type of wireless or wired communication. In another embodiment of the invention, the system 800 is a virtualized computing system capable of executing any or all aspects of software and/or application components presented herein on the computing devices 820, 830, 840. In certain aspects, the computer system 800 is operable to be implemented using hardware or a combination of software and hardware, either in a dedicated computing device, or integrated into another entity, or distributed across multiple entities or computing devices.

By way of example, and not limitation, the computing devices 820, 830, 840 are intended to represent various forms of electronic devices including at least a processor and a memory, such as a server, blade server, mainframe, mobile phone, personal digital assistant (PDA), smartphone, desktop computer, netbook computer, tablet computer, workstation, laptop, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the invention described and/or claimed in the present application.

In one embodiment, the computing device 820 includes components such as a processor 860, a system memory 862 having a random access memory (RAM) 864 and a read-only memory (ROM) 866, and a system bus 868 that couples the memory 862 to the processor 860. In another embodiment, the computing device 830 is operable to additionally include components such as a storage device 890 for storing the operating system 892 and one or more application programs 894, a network interface unit 896, and/or an input/output controller 898. Each of the components is operable to be coupled to each other through at least one bus 868. The input/output controller 898 is operable to receive and process input from, or provide output to, a number of other devices 899, including, but not limited to, alphanumeric input devices, mice, electronic styluses, display units, touch screens, signal generation devices (e.g., speakers), or printers.

By way of example, and not limitation, the processor 860 is operable to be a general-purpose microprocessor (e.g., a central processing unit (CPU)), a graphics processing unit (GPU), a microcontroller, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Programmable Logic Device (PLD), a controller, a state machine, gated or transistor logic, discrete hardware components, or any other suitable entity or combinations thereof that can perform calculations, process instructions for execution, and/or other manipulations of information.

In another implementation, shown as 840 in FIG. 15, multiple processors 860 and/or multiple buses 868 are operable to be used, as appropriate, along with multiple memories 862 of multiple types (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core).

Also, multiple computing devices are operable to be connected, with each device providing portions of the necessary operations (e.g., a server bank, a group of blade servers, or a multi-processor system). Alternatively, some steps or methods are operable to be performed by circuitry that is specific to a given function.

According to various embodiments, the computer system 800 is operable to operate in a networked environment using logical connections to local and/or remote computing devices 820, 830, 840 through a network 810. A computing device 830 is operable to connect to a network 810 through a network interface unit 896 connected to a bus 868. Computing devices are operable to communicate communication media through wired networks, direct-wired connections or wirelessly, such as acoustic, RF, or infrared, through an antenna 897 in communication with the network antenna 812 and the network interface unit 896, which are operable to include digital signal processing circuitry when necessary. The network interface unit 896 is operable to provide for communications under various modes or protocols.

In one or more exemplary aspects, the instructions are operable to be implemented in hardware, software, firmware, or any combinations thereof. A computer readable medium is operable to provide volatile or non-volatile storage for one or more sets of instructions, such as operating systems, data structures, program modules, applications, or other data embodying any one or more of the methodologies or functions described herein. The computer readable medium is operable to include the memory 862, the processor 860, and/or the storage media 890 and is operable be a single medium or multiple media (e.g., a centralized or distributed computer system) that store the one or more sets of instructions 900. Non-transitory computer readable media includes all computer readable media, with the sole exception being a transitory, propagating signal per se. The instructions 900 are further operable to be transmitted or received over the network 810 via the network interface unit 896 as communication media, which is operable to include a modulated data signal such as a carrier wave or other transport mechanism and includes any delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics changed or set in a manner as to encode information in the signal.

Storage devices 890 and memory 862 include, but are not limited to, volatile and non-volatile media such as cache, RAM, ROM, EPROM, EEPROM, FLASH memory, or other solid state memory technology; discs (e.g., digital versatile discs (DVD), HD-DVD, BLU-RAY, compact disc (CD), or CD-ROM) or other optical storage; magnetic cassettes, magnetic tape, magnetic disk storage, floppy disks, or other magnetic storage devices; or any other medium that can be used to store the computer readable instructions and which can be accessed by the computer system 800.

In one embodiment, the computer system 800 is within a cloud-based network. In one embodiment, the server 850 is a designated physical server for distributed computing devices 820, 830, and 840. In one embodiment, the server 850 is a cloud-based server platform. In one embodiment, the cloud-based server platform hosts serverless functions for distributed computing devices 820, 830, and 840.

In another embodiment, the computer system 800 is within an edge computing network. The server 850 is an edge server, and the database 870 is an edge database. The edge server 850 and the edge database 870 are part of an edge computing platform. In one embodiment, the edge server 850 and the edge database 870 are designated to distributed computing devices 820, 830, and 840. In one embodiment, the edge server 850 and the edge database 870 are not designated for distributed computing devices 820, 830, and 840. The distributed computing devices 820, 830, and 840 connect to an edge server in the edge computing network based on proximity, availability, latency, bandwidth, and/or other factors.

It is also contemplated that the computer system 800 is operable to not include all of the components shown in FIG. 15, is operable to include other components that are not explicitly shown in FIG. 15, or is operable to utilize an architecture completely different than that shown in FIG. 15. The various illustrative logical blocks, modules, elements, circuits, and algorithms described in connection with the embodiments disclosed herein are operable to be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application (e.g., arranged in a different order or partitioned in a different way), but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

Other and further embodiments utilizing one or more aspects of the invention described above can be devised without departing from the spirit of Applicant's invention. For example, various seals and seal configurations can seal the components to form the chamber in the transducer housing assembly; various translation devices can be used to move the transducer housing assembly along a component surface in space; various quick disconnect configurations can be used to attach the lens housing; various ultrasonic signal generation and receive devices (combined or separate) can be used to send and/or receive signals from the transducer; and the like can be used to form the transducer housing assembly and the other system equipment, along with other variations can occur in keeping within the scope of the claims.

The above-mentioned examples are provided to serve the purpose of clarifying the aspects of the invention, and it will be apparent to one skilled in the art that they do not serve to limit the scope of the invention. By nature, this invention is highly adjustable, customizable and adaptable. The above-mentioned examples are just some of the many configurations that the mentioned components can take on. All modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the present invention. 

The invention claimed is:
 1. A system for ultrasonic testing of composite materials, comprising: a central housing, having a front end and a back end, defining an interior sealed chamber; a transducer; a fluid connector attached to the central housing; wherein the transducer is located within the interior sealed chamber of the central housing; wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the interior sealed chamber; wherein the front end of the central housing is sealed by a membrane; wherein the membrane is acoustically translucent or acoustically transparent to the coupling fluid; and wherein the transducer is operable to emit and receive ultrasonic waves.
 2. The system of claim 1, wherein the transducer is coupled to a coupling element, and wherein the coupling element sealingly engages the back end of the central housing.
 3. The system of claim 2, wherein the transducer is directly coupled to an elongate member, and wherein the elongate member extends through and sealingly engages with the coupling element.
 4. The system of claim 2, wherein rotation of the coupling element adjusts the position of the transducer relative to the central housing while maintaining sealing engagement with the back end of the central housing.
 5. The system of claim 1, wherein the coupling fluid is water.
 6. The system of claim 1, wherein the fluid connector is operable to pump out air or other gases from the interior sealed chamber before introducing the coupling fluid.
 7. The system of claim 1, further including a mounting bracket attached to the central housing, wherein the mounting bracket is operable to connect to a robotic arm.
 8. The system of claim 1, wherein the central housing further includes at least one surface offset element extending longitudinally outward from the front end of the central housing, wherein the at least one surface offset element is operable to retract by a specified amount.
 9. A method for ultrasonic testing of composite materials, comprising: providing a transducer housing assembly comprising: a central housing, having a front end and a back end, defining an interior sealed chamber; a transducer; a fluid connector attached to the central housing, wherein the fluid connector is operable to connect to a fluid pump; wherein the transducer is located within the interior sealed chamber of the central housing; wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the interior sealed chamber; wherein the front end of the central housing is sealed by a membrane; wherein the membrane is acoustically translucent or acoustically transparent to the coupling fluid; and the fluid pump introducing coupling fluid into the interior sealed chamber via the fluid connector; the transducer emitting ultrasonic waves into a test material; and the transducer housing assembly receiving ultrasonic waves reflected from the test material.
 10. The method of claim 9, further comprising providing a device, including a processor and a graphical user interface (GUI), in network connection with the transducer housing assembly, the processor processing the received ultrasonic waves to produce test results, and the GUI displaying the test results in graphical form.
 11. The method of claim 9, wherein the transducer is coupled to a coupling element, and wherein the coupling element sealingly engages the back end of the central housing.
 12. The method of claim 11, wherein the transducer is directly coupled to an elongate member, and wherein the elongate member extends through and sealingly engages with the coupling element.
 13. The method of claim 11, wherein rotation of the coupling element adjusts the position of the transducer relative to the central housing while maintaining sealing engagement with the back end of the central housing.
 14. The method of claim 9, wherein the coupling fluid is water.
 15. The method of claim 9, further comprising the fluid pump pumping out air or other gases from the interior sealed chamber before introducing the coupling fluid.
 16. The method of claim 9, wherein the transducer housing assembly further comprises a mounting bracket attached to the central housing, wherein the mounting bracket is operable to connect to a robotic arm.
 17. The method of claim 9, wherein the central housing of the transducer housing assembly further includes at least one surface offset element extending longitudinally outward from the front end of the central housing, wherein the surface offset elements are operable to retract by a specified amount.
 18. The method of claim 9, further comprising applying an external coupling material to the surface of the test material before the transducer emits ultrasonic waves into the test material.
 19. A system for ultrasonic testing of composite materials, comprising: a central housing, having a front end and a back end, defining an interior sealed chamber; a coupling element sealingly engaged with the back end of the central housing and coupled with a transducer; a fluid connector attached to the central housing; wherein adjustment of the coupling element moves the transducer relative to the central housing; wherein the fluid connector is operable to connect with a fluid pump to introduce coupling fluid into the interior sealed chamber; wherein the front end of the central housing is sealed by a membrane; wherein the membrane is acoustically translucent or acoustically transparent to the coupling fluid; and wherein the transducer is operable to emit and receive ultrasonic waves.
 20. The system of claim 19, wherein the central housing further includes at least one surface offset element extending longitudinally outward from the front end of the central housing, wherein the at least one surface offset element is operable to retract by a specified amount. 